Electromagnetic relay



s. H. T 'OWNER' 2, "BLBCTROIAGNBTIC RELAY 1104 Jui 20; 1943 Inventor W when" Jamar- Allo -nay Patented 26, 1947 awcraomommc RELAY Stanley Herbert Towner,

signor, by mesne assi Standard Electrl London, England, asgnments, to International c Corporation,

New York,

N. Y., a corporation of Delaware Application July 20, 1943, Serial No. 495,447 In Great Britain All'tlllt 18, 1942 5Claims.

tacts, permanent displacement of armature or short circuit of contacts to frame. Such failures may occur "when relays are (a) handled without due care during mounting and wiring (b) sub.

iected to severe jolts in transport or (c) subjected to continuous vibration, and in each case are primarily due to movement of the armature away from the knife edge. This movement is partially restricted by the armature retaining screw and spring (see Fig. 1) but manufacturing tolerances do not permit definite location of the armature and in general it is possible for the armature studs to move out of engagement with the lifting pins.

The object of the present invention is to provide means whereby the armature is held in position with just suilicient freedom of movement for satisfactory operation independent of manufacturing tolerances.

In the accompanying drawing,

Fig. 1 shows the relevant part of a relay;

Fig. 2 shows its modification in accordance with one embodiment of the present invention;

Fig. 2a shows one form of an adjustable nut for the relay; and

Fig. 3 shows its modification in accordance with another embodiment of the present invention.

As shown in Fig. l, the armature I l is pivotally support on a. knife edge at the forward end of the yoke 2. Two armature studs l3 (one only standard being shown) engage operating pins H to operate. the contact springs sets IS.

The armature II, is held in place by a washer it acted upon by a spring ll encircling a retaining screw it.

The failures referred to above may in many cases be due to a twisting of the armature ll about one point in its knife edge, with the result that one of the operating plus it slips off its armature stud l3 and rides directly on the surface of the armature. The present invention reduces the frequency of failure by an armature retaining means which confines the movement of the armature to a pivotal movement about the knife edge.

As shown in Fig. 2, the armature retaining screw is replaced by a stud 19 secured in the yoke 12 at the required angle and passing through the armature hole. The outer portion of the stud is threaded and carries an adjustable self-locking nut 20 which is tightened to give the required armature freedom, 1. e., to within .010" of the .surface of the armature when the latter is held against the knife edge. v

The stud I! may be secured in a threaded hole in the yoke, the end 2| being staked or rivetted over to prevent rotation when the nut is adjusted.

Where it passes through the armature the stud I! should have a smooth surface as at 22 (not threaded) and may have circular, hexagonal or other cross section as required to provide adequate location and facilitate-assembly.

The adjustable nut may be of the form shown in Fig. 2a, or other forms provided with some means of locking may be used.

As shown in Fig. 3, the armature screw and spring of Fig. 1 are replaced by a shouldered screw 23 carrying a plain washer 24 and a compressible washer 25 which assumes the required thickness as the screw 23 is tightened in the yoke. The required freedom of movement of the armature is obtained by placing a suitable gauge between the armature H and the flat washer 24 durin assembly.

The compressible washer 25 may take the form of a cupped washer of brass or copper which is sufficiently flexible to be distorted by the pressure of the screw when tightened in the normal manner and sufficiently rigid to withstand handling vibration. The maximum possible distortion must exceed the total variation in dimensions of armature, yoke, screw and washer along the axis of the screw. v

The following claims severally recite the features of the invention.

What is claimed is:

1. A relay of the type in which the armature is supported on a knife edge on the yoke comprising in combination with a yoke providing a knife edge bearing and an armature formed to provide a co-operating bearing groove in the inner surface of its bend and provided with an opening therethrough, of retaining means for the armature consisting of a connecting member engaging the yoke to pass freely through the armature opening, said member substantially intersecting said knife edge a non-resilient stop element on the projecting end of the connecting member adapted for positioning at a distance from said knife edge such that said armature is restricted to 8- 9 otal movement about said knife edge.-

2. A relay as claimed in claim 1 wherein the stop element comprises a plain washer engaging the armature outer surface and a compressible washer outwardly of the plain washer in engagement therewith, the latter of which is compressed to adjust properly the distance between said knife edge and said stop element.

3. A relay as claimed in claim 1 wherein the retaining means includes a compressible washer adapted to be adjustable by bending to vary the efiective distance of the stop from the knife-edge bearing.

4. An electromagnetic relay including yoke and armature members, one 01' said members having a knife edge for engaging the other to permit relative oscillating movement therebetween about said knife edge, a guide element in engagement with one of said members and extending through an opening in the other, said element substantially intersecting said knife edge, a, non-resilient stop member associated with said guide element, said stop member being adjustable to fix the distance between said stop member and said knife edge such that said other member is restricted to a pivotal movement about said knife edge.

5. An electromagnetic relay including a yoke having a knife edge, an armature supported on said knife edge, a stud bolt extending through aligned openings in said armature and knife edge, said stud bolt having a lower threaded portion secured to said yoke, a middle non-threaded portion passing through the armature opening and an upper threaded portion above the armature, and a self-locking nut threaded on said upper portion, the distance between said knife edge and the upper limit of said non-threaded portion being selected such that when said nut is moved to said upper limit, the armature is restricted to a pivotal movement about said knife edge.

STANLEY HERBERT TOWNER.

REFERENCES CITED The following references are of record in the file of this patent:

FOREIGN PATENTS Number Country Date 190,826 Switzerland Aug. 2, 1937 91,683 Sweden Jan, 5, 1938 355,667 Great Britain Aug. 21, 1931 465,133 Great Britain May 3, 1937 4,576 Australia Oct. 19, 1931 358,070 Great Britain Oct. 5, 1931 

